1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* uio_pci_generic - generic UIO driver for PCI 2.3 devices |
3 | * |
4 | * Copyright (C) 2009 Red Hat, Inc. |
5 | * Author: Michael S. Tsirkin <mst@redhat.com> |
6 | * |
7 | * Since the driver does not declare any device ids, you must allocate |
8 | * id and bind the device to the driver yourself. For example: |
9 | * |
10 | * # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id |
11 | * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind |
12 | * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind |
13 | * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver |
14 | * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic |
15 | * |
16 | * Driver won't bind to devices which do not support the Interrupt Disable Bit |
17 | * in the command register. All devices compliant to PCI 2.3 (circa 2002) and |
18 | * all compliant PCI Express devices should support this bit. |
19 | */ |
20 | |
21 | #include <linux/device.h> |
22 | #include <linux/module.h> |
23 | #include <linux/pci.h> |
24 | #include <linux/slab.h> |
25 | #include <linux/uio_driver.h> |
26 | |
27 | #define DRIVER_VERSION "0.01.0" |
28 | #define DRIVER_AUTHOR "Michael S. Tsirkin <mst@redhat.com>" |
29 | #define DRIVER_DESC "Generic UIO driver for PCI 2.3 devices" |
30 | |
31 | struct uio_pci_generic_dev { |
32 | struct uio_info info; |
33 | struct pci_dev *pdev; |
34 | }; |
35 | |
36 | static inline struct uio_pci_generic_dev * |
37 | to_uio_pci_generic_dev(struct uio_info *info) |
38 | { |
39 | return container_of(info, struct uio_pci_generic_dev, info); |
40 | } |
41 | |
42 | static int release(struct uio_info *info, struct inode *inode) |
43 | { |
44 | struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info); |
45 | |
46 | /* |
47 | * This driver is insecure when used with devices doing DMA, but some |
48 | * people (mis)use it with such devices. |
49 | * Let's at least make sure DMA isn't left enabled after the userspace |
50 | * driver closes the fd. |
51 | * Note that there's a non-zero chance doing this will wedge the device |
52 | * at least until reset. |
53 | */ |
54 | pci_clear_master(dev: gdev->pdev); |
55 | return 0; |
56 | } |
57 | |
58 | /* Interrupt handler. Read/modify/write the command register to disable |
59 | * the interrupt. */ |
60 | static irqreturn_t irqhandler(int irq, struct uio_info *info) |
61 | { |
62 | struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info); |
63 | |
64 | if (!pci_check_and_mask_intx(dev: gdev->pdev)) |
65 | return IRQ_NONE; |
66 | |
67 | /* UIO core will signal the user process. */ |
68 | return IRQ_HANDLED; |
69 | } |
70 | |
71 | static int probe(struct pci_dev *pdev, |
72 | const struct pci_device_id *id) |
73 | { |
74 | struct uio_pci_generic_dev *gdev; |
75 | struct uio_mem *uiomem; |
76 | int err; |
77 | int i; |
78 | |
79 | err = pcim_enable_device(pdev); |
80 | if (err) { |
81 | dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n" , |
82 | __func__, err); |
83 | return err; |
84 | } |
85 | |
86 | if (pdev->irq && !pci_intx_mask_supported(pdev)) |
87 | return -ENODEV; |
88 | |
89 | gdev = devm_kzalloc(dev: &pdev->dev, size: sizeof(struct uio_pci_generic_dev), GFP_KERNEL); |
90 | if (!gdev) |
91 | return -ENOMEM; |
92 | |
93 | gdev->info.name = "uio_pci_generic" ; |
94 | gdev->info.version = DRIVER_VERSION; |
95 | gdev->info.release = release; |
96 | gdev->pdev = pdev; |
97 | if (pdev->irq && (pdev->irq != IRQ_NOTCONNECTED)) { |
98 | gdev->info.irq = pdev->irq; |
99 | gdev->info.irq_flags = IRQF_SHARED; |
100 | gdev->info.handler = irqhandler; |
101 | } else { |
102 | dev_warn(&pdev->dev, "No IRQ assigned to device: " |
103 | "no support for interrupts?\n" ); |
104 | } |
105 | |
106 | uiomem = &gdev->info.mem[0]; |
107 | for (i = 0; i < MAX_UIO_MAPS; ++i) { |
108 | struct resource *r = &pdev->resource[i]; |
109 | |
110 | if (r->flags != (IORESOURCE_SIZEALIGN | IORESOURCE_MEM)) |
111 | continue; |
112 | |
113 | if (uiomem >= &gdev->info.mem[MAX_UIO_MAPS]) { |
114 | dev_warn( |
115 | &pdev->dev, |
116 | "device has more than " __stringify( |
117 | MAX_UIO_MAPS) " I/O memory resources.\n" ); |
118 | break; |
119 | } |
120 | |
121 | uiomem->memtype = UIO_MEM_PHYS; |
122 | uiomem->addr = r->start & PAGE_MASK; |
123 | uiomem->offs = r->start & ~PAGE_MASK; |
124 | uiomem->size = |
125 | (uiomem->offs + resource_size(res: r) + PAGE_SIZE - 1) & |
126 | PAGE_MASK; |
127 | uiomem->name = r->name; |
128 | ++uiomem; |
129 | } |
130 | |
131 | while (uiomem < &gdev->info.mem[MAX_UIO_MAPS]) { |
132 | uiomem->size = 0; |
133 | ++uiomem; |
134 | } |
135 | |
136 | return devm_uio_register_device(&pdev->dev, &gdev->info); |
137 | } |
138 | |
139 | static struct pci_driver uio_pci_driver = { |
140 | .name = "uio_pci_generic" , |
141 | .id_table = NULL, /* only dynamic id's */ |
142 | .probe = probe, |
143 | }; |
144 | |
145 | module_pci_driver(uio_pci_driver); |
146 | MODULE_VERSION(DRIVER_VERSION); |
147 | MODULE_LICENSE("GPL v2" ); |
148 | MODULE_AUTHOR(DRIVER_AUTHOR); |
149 | MODULE_DESCRIPTION(DRIVER_DESC); |
150 | |